Modern farming practices strive to increase yields of agricultural fields. Yields can be increased by increasing plant populations. Efforts have been made to increase plant populations by planting row crops with narrower row spacing, allowing more rows to be planted in a field, which may require harvesting with special equipment configured for harvesting narrow rows, such as narrow row heads for the harvesting implements. Twin-row planters have been developed that plant seeds as a pair of row segments that are closely width-spaced. Each pair of row segments is spaced from adjacent pairs of row segments at conventional row widths, allowing conventional heads to be used on the harvesting implements. This is typically done by mounting a pair of row units with a corresponding pair of seed meters at each row segment, with the seed meters longitudinally staggered in a forward seed meter and rearward seed meter relationship. Seed meters of twin-row planters are typically also made from components are narrower than in non-twin-row planters, with each of the seed meters separately mounted to the toolbars of the twin-row planters. This longitudinal staggering and relatively narrower component configuration of the paired row units provides the mounting space needed for separately mounting the paired row units and their corresponding pair of seed meter drive systems from a toolbar of the twin-row planter.